The technology of the present disclosure relates to a fixing device and an image forming apparatus.
Conventionally, there has been known a fixing device provided with an endless fixing belt heated by a heating part and a pressure roller brought into press contact with the fixing belt. In this fixing device, when a recording paper passes through between the fixing belt and the pressure roller, toner on the recording paper is heated and pressed and is fixed to the recording paper.
In this type of fixing device, since a heating surface of the fixing belt is not able to follow unevenness (unevenness of the surface of the recording paper) of a toner layer formed on the recording paper, uneven heating occurs. As a consequence, glossiness becomes high in a part in which a heat transfer amount is large, that is, a part in which toner has been sufficiently molten, while glossiness becomes low in a part in which the heat transfer amount is small, that is, a part in which the toner has not been sufficiently molten. Therefore, there is a problem that uneven glossiness occurs in an image.
In order to cope with the problem, there has been proposed a fixing device in which the thickness of an elastic layer of an outer peripheral part of the fixing belt is set to be equal to or more than 100 μm. By so doing, the outer peripheral part of the fixing belt is allowed to follow the unevenness of the recording paper, so that it is possible to solve the aforementioned uneven glossiness problem.
Furthermore, there has also been proposed a fixing device in which vibration occurs in a nip portion serving as an abutting portion between a fixing roller and the pressure roller by vibrating a support shaft of the fixing belt by a ultrasonic generator.